Patent GB-1425356-A (GB)
Title: Pressure reducing control device for the hydraulic control circuit of an automatic transmission
IPC: F16H61/18
Filed: 1973-10-15
Abstract: 1425356 Change speed gear NISSAN JIDOSHA KK 15 Oct 1973 [20 Oct 1972] 47978/73 Heading F2D In an automatic transmission on a motor vehicle having ratio-establishing friction clutches and brakes 4...12, applied hydraulically under control of a manual selector valve 42 and automatic shift valves 45, 46, 47, a first individual pressure regulator (low-reverse regulator) 51 is connected between a first automatic shift valve (1-2 valve) 45 and a first friction brake 9, and supplies a regulated reduced pressure to that only when loaded by pressure 211 received from the first shift valve 45; and a second individual pressure regulator 52 similarly supplies a regulated reduced pressure to a second friction brake (second ratio two-way brake) 10 only when loaded by pressure 182 received from the manual selector valve 42 in manual 2 setting. In addition the low-reverse regulator 51 receives its loading pressure 211 through the 1-2 shift valve 45 only when the manual selector valve 42 is in 1 setting, and hence on entry into manual 1 or 2 the corresponding brake pressure is reduced to provide smooth engine braking Function summary.-Automatic 1-2, 2-3 and 3-4 shift valves 45, 46, 47 are actuated by opposing fluid pressures 186, 208 responsive respectively to engine intake depression by a TV regulator valve 44, and to a governor valve comprising primary and secondary outputmounted masses 59, 60, producing primary governor pressure 189 amplified by an amplifying regulator valve 48 to a line 208. Accelerator kickdown shift is produced by a solenoid valve 49, which produces kickdown by disabling the governor amplifier valve 48 so that the relatively lower primary governor pressure 189 acts on the shift valves in place of amplified pressure 189. In addition the solenoid valve 49 is also actuated by accelerator release to co-operate with a TV actuated idler valve 50 to establish fourth ratio at engine idle thus eliminating creep, first ratio being subsequently established by accelerator depression for starting. A separate hysteresis valve 53 produces hysteresis and snap action in the shift valves. Gear arrangement.-Three reduced ratios, direct drive and one reverse are provided by three sun-ring-planet trains 5, 7, 8, connected as shown and controlled by an input clutch 5, used in all forward ratios, an input clutch 4, used for direct drive and reverse, and four brakes, a first, 11, rendering effective a low oneway brake 14 for automatic low, a second, 10, bridging the brakes 14, 11 for manual two-way low and reverse, a third, 9, bridging a one-way automatic brake 33 for two-way manual second, and a fourth, 12, with apply and release sides 34, 35, for two-way third. The two clutches 4, 5 together produce direct drive. Fluid pressure supply and regulation.-A single input driven pump 41 supplies line pressure 64 at a level controlled by a main regulator valve 43, subject to pressure-increasing upward loading by a spring 66 and to TV pressure 186, 185, acting on differential lands, such TV pressure being substituted by full line pressure through a shuttle valve 57, when a line 181 from the manual valve 42 receives line pressure 64, 77 in 3, 2 and 1 settings, whereupon line pressure is no longer TV responsive but has full value even at low throttle for engine braking. The regulator valve 43 has pressure decreasing downward loading by line pressure acting at 67 from a line 180 pressurized in D setting only of the manual valve 42, resulting, in effect, in pressure augmentation in manual 1, 2 and 3 settings. Additional downward loading is provided by line pressure 64 acting through a restrictor 178, and to line pressure 184 from the idle valve 50 to reduce line pressure at engine idle thus softening the shift to D or R. The individual regulator valves 51, 52 act as described below.  Shift valves.-The manual valve 42 has settings R N D and three manual settings 3, 2, 1, in each of which upshift above the selected ratio is prevented under any speed condition, but in which entry to 2 or 1 is delayed by governor pressure until speed is below a predetermined safe value. In both 3 and 2 settings, automatic shifts to lower ratios, e.g. 3-2, 2-1, at higher speeds than in Drive are possible. Automatic shift valves.-1-2, 2-3, and 3-4 shift valves 45, 46, 47 are loaded upwards for upshift by governor pressure 189 which is normally amplified to a line 208, by the amplifier valve 48, which latter is overridden by kickdown to supply primary governor pressure 189 to the shift valves. Downward, downshift loading is provided by springs and by TV pressure 186, 185 reaching differential lands of the shift valves through shuttle valves 54, 55, 57, which, in the respective 1, 2, 3 manual settings of the manual valve 42, change over to substitute full line pressure for TV, whereupon the shift valves are no longer TV sensitive and hence maintain high shift speeds at closed throttle for engine braking. Line pressure is additionally applied to the upper ends of the shift valves in the manual settings. Hysteresis action in the 2-3 and 3-4 shift valves 46, 47, is produced by the hysteresis valve 53. In all manual valve settings except 1, 2 and 3 the hysteresis valve is upwardly loaded by TV pressure 186, 185, 153. Line pressure 64 is thereby regulated into a hysteresis pressure line 197, which acts on differential lands of the 2-3 and 3-4 shift valves 46, 47. In the downshifted position the 2...3 valve 46 is loaded downwardly by spring, by TV pressure 185, 55, 105, and by hysteresis pressure 197, 106. During 2-3 upshift the hysteresis port 106 becomes blocked, eliminating that pressure, to produce rapid upshift movement of the valve. Finally the hysteresis pressure 197, 106, previously acting between lands 100c, 100d, is replaced by TV pressure at 105, which pressure is lower than hysteresis pressure, so that return downshift is at a lower speed than that of upshift. Action for the 3-4 valve 47 is similar, but the hysteresis pressure is not used in the 1-2 valve 45. In manual settings 1, 2 and 3 pressurization of a line 181 changes over the shuttle valve 57 and substitutes full line pressure for TV at the port 153 of the hysteresis valve 53 which is thereby forced fully upwards to substitute line pressure for hysteresis pressure in the shiftvalve load line 197, to maintain the downshift setting of the shift valves. For the same purpose line pressure is additionally applied to the upper ends of all the shift valves 45, 46, 47 through manual valve lines and the shuttle valves 54, 55, 57. Kickdown valve 49.-With solenoid 160 deenergized, line pressure 64, 205, through a restrictor 156, builds up above the spool of the kickdown valve 49 forcing the spool down to exhaust a line 207. Energizing the solenoid 160 exhausts the upper chamber of the valve, permitting a spring to lift the valve spool, thus supplying line pressure 64, 157 to the line 207 leading to the idle valve 50. Under full throttle condition, TV pressure 185, now at maximum, raises the spool of the idle valve 50, passing kickdown pressure 207 through a line 202 to force down the spool of the governor pressure amplifier valve 48, which thereupon ceases to amplify and supplies primary governor pressure 189, through line 208, 209 directly to the shift valves 45, 46, 47, thus reducing all their shift speeds and producing successive kickdowns. Anti-creep.-Accelerator release also energizes the kickdown valve solenoid 160 to pressurize the line 207, but since, at this time, TV pressure 185 is at its minimum, the idle valve 50 is in its lowest position, and line pressure 207 passes into a line 184, where it changes over a shuttle valve 209 and passes directly to the shift valves 45, 46, 47, replacing governor pressure and producing upshift of all the valves to establish fourth ratio. At the same time line pressure 184 acts downwardly on the main regulator valve 43 to reduce system pressure, to soften the subsequent entry into drive or reverse. This idle action is prevented in 1, 2, 3 manual settings to preserve engine braking, by increasing the downward loading of the main regulator valve 43, by substituting full line pressure from the manual valve through the shuttle valve 57 in place of TV pressure 186 in the line 185. Individual regulator valves.-These two items 51, 52, serve respectively the low-reverse twoway brake 9 and the second ratio two-way brake 10 and are thus used in manual 1, R and 2 settings only. Selection of reverse by the manual valve 42 supplies line pressure 64 through ports 77, 76, line 191 and the lowreverse regulator 51 to the low-reverse brake 9, and through the line 191 and shuttle valve 56 to the direct reverse clutch 4. Delivery pressure 192 holds the spool of the low-reverse regulator valve 51 fully downwards, so that full line pressure is delivered to the brake 9. In manual 1 line 180 pressurizes the forward clutch 5 directly, as in all forward ratios, and of manual valve lines 181, 182, 183, which are also pressurized, the first two downshift the 2-3 and 3-4 shift valves 46, 47, whilst the third, 183, downshifts the 1-2 valve 45, and also, through the 1-2 valve and line 211, pressurizes two ports of the low-reverse regulator 51, one, 137, providing upward loading for regulating brake pressure 192 to a value lower than line pressure. Thus the low-reverse regulator valve 51 reduces the pressure 192 supplied to the low-reverse brake 9 only when that valve 51 receives an input 211 from the 1-2 shift valve 45, and this occurs when the manual selector valve 42 is in 1 setting. The second individual pressure regulator 52 regulates a reduced pressure supply 210 to the second ratio two-way brake 10 only when that regulator 52 is loaded upwards by line pressure 182 supplied to it in manual 2 setting only of the manual selector valve 42.